code: def run_dist(rank, world_size, port):
      colossalai.launch(
          config=dict(),
          rank=rank,
          world_size=world_size,
          port=port,
          host="localhost",
      )
  
      exam_zero_1_torch_ddp_ckpt()
  
file_path: ColossalAI/tests/test_zero/test_low_level/test_zero_ckpt.py
imports: import copy
  import pytest
  import torch
  import torch.nn
  from torch.nn.parallel import DistributedDataParallel
  from torch.testing import assert_close
  import colossalai
  from colossalai.testing import rerun_if_address_is_in_use, spawn
  from colossalai.testing.random import seed_all
  from colossalai.zero import LowLevelZeroOptimizer
label_desc: Use image node_id 3 for calling a global function with example usage: run_dist(rank, world_size, port) without return types